Here are the sizes of the particle ladder by TEM. I compare to the previous unmodified DLS results in this table.
| Manufacturer’s Size | TEM size | Stdev | DLS Size |
| 5 | 6.6 | .6 | 8 |
| 10 | 7.8 | .9 | 9.4 |
| 15 | 12.7 | .9 | 13.2 |
| 20 | 16.0 | 1.5 | 17.2 |
| 30 | 25.7 | 2.1 | 28.8 |
| 40 | 34.3 | 2.3 | 30.7 |
The particles aren’t exactly the sizes the manufacturer is claiming, and DLS seems to be a reasonable measurement.
While measuring these guys I found some interesting particles in the mixture, like these triangles and hexagons:
So I think I have confirmed that PDMS is at least one of if not the major contributor to the contact angle problems in the UV-ozone system. Control image before any treatment: I then dried the chip and placed it in the UV-ozone system with two slides that each had two strips of PDMS. Since…
Along with differently sized square membranes, I also designed a wafer with different sizes of slits. On each chip, there is a 4000, 2000, 1000 and 500um long window. The thicknesses of these windows are 200, 100, 50 and 25um. I’m interested to see if there is an aspect ratio that causes endothelial cell alignment/tubulogenesis. …
I spent some more time in understanding the numbers I am getting for our device simulations. In my simulations, I am assigning a conductivity value for my cell layer. Technically, from this information and by knowing the thickness and area of the cell layer, I can analytically calculate the value of resistance that the cell…
In all of the below graphs, the x-axis has the same scale for easy comparison (-10 nm to 80 nm diameter). The Y-axis varies from plot to plot, but since we care more about pore density than actual numbers of pores, I have left these numbers out. Here is an example full plot with MATLAB’s…
Carrying our membrane functionalization work forward we attempted to work in both the polymer chemistry space and the KODE nonspecific binding space. With the results shown below the KODE molecule pathway has shown much more promise than the polymer chemistry pathway. This, for the moment, has provided the conclusions that fuel the title of this…
Introduction: Fibroblasts: Dermal fibroblasts are cells within the dermis layer of skin which are responsible for generating connective tissue and allowing the skin to recover from injury. A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are…
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This speaks well for the DLS system, a little less well for the manufacturer’s control.
So, now that we have some confidence in our sizes, what is the sharpest fractionation we’ve seen so far?
As far as conclusive separation goes, the best we have seen so far is 6.6 nm from 16.0 nm in 10mM KCl.
I haven’t had membranes yet to test this new ladder, but with all the good stuff coming through recently this should happen soon.